Who do I write to if I am trying to find the location of my grandfathers business in Berlin in 1923?I have been trying to find the email address of the chamber of commerce in Berlin. Can anyone help?ThanksCarol KarpTucson Arizona

Numerous directories for Berlin are viewable (and somewhat searchable) at https://www.zlb.de/besondere-angebote/berliner-adressbuecher.html. Many have a section organized by name, a section organized by street address, and a section organized by type of business. You can browse/search yourself on that site. I would make them searchable here, too, but I don't have access to good enough scans in most cases.